The object of this project is to study the biochemistry of a collagen-dependent cell attachment protein (c-CAP). Several aspects of the interaction of c-CAP with both collagen and cultured cells have been described. Recently, we have described a new method, termed bioautography, that permits one to study electrophoretic mobility differences between various c-CAP's. We have now isolated a protein from the conditioned medium of hepatoma cells that mediates cell attachment to collagen which has different biochemical properties than the serum c-CAP we previously described. The aim of our laboratory is to isolate other cell attachment proteins with the aid of bioautography.